The crash happened in Long Grove just after 10 a.m. along Route 53, just north of Lake Cook Road.
The sheriff's office said a man driving a 2021 Isuzu box truck was traveling northbound on Route 53. For an unknown reason, it crossed into the southbound lanes and into the path of a 2016 Freightliner semi, which was hauling a loaded trailer. The two vehicles collided head-on.
The driver of the box truck died, and his passenger was transported to a local hospital in critical condition, the sheriff's office said. The semi's driver was taken to a local hospital with serious injuries.
The Lake County Sheriff's Office Technical Crash Investigations Unit is investigating.